A new confinement model for FRCM confined concrete

Confined concrete by means of FRCM (Fabric Reinforced Cementitious Matrix), also known as TRM (Textile Reinforced Mortar), may exhibit alternative stress–strain behaviors, depending on different variables including the unconfined concrete strength, concrete cross-section, fibers type and number of layers. Specifically, increasing the confinement level, the experimental observed response changes from a softening to a hardening one, after an initial peak that coincides roughly to that of the unconfined strength. To consider the peculiar behavior of FRCM-confined concrete, a new analytical model is proposed in this work. The formulation allows to calculate both the first and ultimate peak strength values, being more adherent to the real observed experimental behavior of FRCM-confined concrete members. The model is calibrated on a set of experimental data obtained by the same authors, and then its accuracy is validated on a different, larger dataset. Model performance indicators are compared to those calculated for other existing formulations, demonstrating the goodness of the new proposal.